1. Field of the Invention
The present disclosure relates to magnetic resonance imaging, and in particular to a magnetic resonance imaging apparatus being used for a diagnosis of various diseases by using a magnetic resonance image, and a diffusion-weighted image acquiring method thereof.
2. Description of the Related Art
In general, a medical imaging apparatus is an apparatus configured to provide an image by acquiring information of a patient. The medical imaging apparatus may include an x-ray apparatus, an ultrasonic wave diagnostic apparatus, a computerized tomography apparatus, and a magnetic resonance imaging (MRI) apparatus.
From the above medical imaging apparatuses, the magnetic resonance imaging apparatus has a relative flexibility of the image photographing conditions, and provides various images with diagnostic information and superior contrast of soft tissue, thereby taking an important position in the diagnostic field using a medical image.
Magnetic Resonance Imaging (MRI) refers to acquiring an image of the density and the physicochemical characteristics of body tissues based on the characteristics of an atomic nucleus by generating a nuclear magnetic resonance phenomenon at a hydrogen atomic nucleus, or other atomic nuclei not limited to hydrogen, of the body by use of a magnetic field, which is not harmful to a human body, and a radio frequency (RF) signal, which is a specific ionization radiation.
In more detail, the magnetic resonance imaging apparatus is an image diagnostic apparatus configured to diagnose the inside of a human body by converting the energy emitted from an atomic nucleus into a signal after supplying a constant frequency and energy to the atomic nucleus in a state of the atomic nucleus applied with a constant magnetic field.
Since a proton included in an atomic nucleus is provided with spin angular momentum and a magnetic dipole, when a magnetic field is applied, the proton is aligned in a direction of the magnetic field, and the atomic nucleus performs a precession around the direction of the magnetic field. By using the precession, an image of a human body may be acquired through a nuclear magnetic resonance phenomenon.
Meanwhile, in the field of a magnetic resonance imaging, a diffusion-weighted image is being used in the prior art in order to acquire various shapes of tissues using imaging contrasts, and the diffusion-weighted image refers to an image having a difference of the contrasts weighted according to the degree and the direction of diffusion of the molecules generated inside the tissue of a human body by applying diffusion gradient magnetic fields in several directions.
In the prior art, as the need for a diffusion-weighted image has increased, the development of a technology capable of reducing the time needed to acquire an image while minimizing a motion artifact is in demand.